Vehicle carried boom



y 1966 A. KRYNYTZKY ETAL 3,253,677

VEHICLE CARRIED BOOM 4 Sheets-Sheet 1 Filed Dec. 24, 1963 ,677 y 31 1966 A. KRYNYTZKY ETAL 3,253

VEHICLE CARRIED BOOM 4 Sheets-Sheet 4 Filed Dec. 24, 1953 VENTOR-S mmaa I6 1 1 3 W M! mnegs United States Patent 3,253,677 VEHICLE CARRIED BOOM Alexrmder Krynytzky, Ebenezer, Otto Hoilm-ann, Kenmore, and Edward J. Zajac, Buffalo, N.Y., assignors to Sterling Precision Corporation, Elmira, N.Y., a corporation of Delaware Filed Dec. 24, 1963, Ser. No. 333,096 8 Claims. (Cl. 1822) This invention relates to a vehicle carried boom and is more particularly directed to a double arm boom carried by turntable on a truck, each arm being capable of being individual elevated and the outboard end of the top arm carrying a platform having a water nozzle or nozzles to be used for firefighting. Such a double arm boom is capable of being raised to great height determined by the combined length of the two arms; because of its compact length when retracted it can be moved along the highway on fire trucks; because of its double height determined by the combined length of the two arms; because of its double arm construction it can be raised in confined quarters where it would be impossible to raise a single arm to the same height; by reason of the turntable mounting the platform can be moved in any direction, both horizontally and vertically, notwithstanding the presence of adjacent structure; and it is also possible to lower the platform down over structures, such as a standing wall, between the supporting chassis and the platform.

With vehicles having double armbooms of this type, difiiculty has been encountered in lowering the boom structure far enough to be able to get into garage door openings of fire houses. Different solutions have been proposed, such as folding Windshields and the like, to overcome this disadvantage, but this is obviously a distinct disadvantage with fire equipment where in order to make the vehicle roadable it is necessary to drive the vehicle out of the firehouse; raise the boo-m structure a short distance; and unfold the windshield to its operative condition to enable the driver to have full visibility of all sides of the roadway ahead.

It is accordingly an important object of the invention to provide a double arm boom for a wheeled vehicle which, when completely collapsed, has its high point at such low elevation to enable the vehicle to be moved into and out of normal garage doors of firehouses, the boom being collapsed by merely lowering the boomstructure on a supporting rest and without interfering with the windshield or any other structure of the vehicle; without interfering with the driver or other firemen in the truck; and without interfering with the full vision of the driver ahead and on opposite sides of the vehicle. This is accomplished by nesting a part of one arm, namely the top boom arm, within the bottom boom arm as the double ar-m boom is brought to its fully lowered position.

Another object is to provide a simple telescopic cylinder and piston rod form of hydraulic lift or jack to extend and retract the top arm with reference to the bottom arm of the boom and which does not interfere with the internesting of the boom arms as they approach their fully collapsed condition. This is achieved by making the connected portions of these boom arms of channel shape in cross section with their channels opening toward each other and with the ends of the telescopic hydraulic lift pivotally connected to these arms within 3,253,677 Patented May 31, 1966 their channels, so that the hydraulic lift also nests within the boom arms as they approach their fully collapsed condition.

Another object is to provide such a double arm boom the arms of which can be brought substantially to vertical positions thereby to elevate a platform or the like at the outboard end of the top boom to a great height.

Another object of the invention is to provide a double arm boom which has the required strength and sturdiness to support the platform free from swaying or uncertain movements, both horizontally and vertically, and so that when the operator on the platform moves the platform in any direction, either horizontally, or vertically or both, the platform will move in the direction with complete certainty and freedom from jerks or swaying movements and will also come to a stop with equal certainty.

Another object is to provide such a double arm boom which is light in weight so that a minimum of inertia is involved in moving the platform from place to place.

Another object is to provide a simple mechanism, particularly that which extends along the top arm of the boom, for maintaining the platform level at all times. This is accomplished by a rotating shaft extending lengthwise of the top boom arm and having gearing at its opposite ends, in contradistinction to the external parallel linkage or cable arrangements usually employed for this purpose.

When used for firefighting purposes one or more water nozzles are provided on the platform and water lines are provided along the double arm boom to supply water thereto. It is another object of the present invention to provide a simple and effective means for supplying water through the turntable to the water line or lines carried by the bottom lbOOIl'l arm, this being achieved by bringing the water supply line up coaxial with the turntable and then through a tubular trunnion or trunnions carrying the lower boom arm on the turntable so that the water line or lines are completely contained within the boom supporting mechanism until the line or lines emerge to extend along the arms of the boom to the nozzle or nozzles on the platform.

Another object is to provide such a boom structure and water supply therefor which is simple in construction and low in cost, considering the function which it performs.

Other objects and advantagesof the invention will be apparent from the following description and drawings in which:

FIG. 1 is a side elevational view of a fire truck equipped with a double arm boom embodying the present invention and showing, in full lines, the boom in its retracted or lowered position and showing, in dot-dash lines, the boom in a partially extended or raised position. In this view a portion of the conventional water line has been removed.

FIG. 2 is an enlarged fragmentary vertical section taken generally along line 2-2, FIG. 1.

'FIG. 3 is an enlarged fragmentary horizontal section taken generally on line 33, FIG. 1.

FIG. 4 is an enlarged fragmentary section taken generally on line 4-4, FIG. 1.

FIG. 5 is an enlarged fragmentary section taken generally on line 55, FIG. 1.

FIG. 6 is an enlarged fragmentary section taken generally on line 66, FIG. 1.

FIG. 7 is an enlarged fragmentary vertical section taken generally on line 77, FIG. 1.

FIG. 8 is a fragmentary vertical longitudinal section through the connected ends of the arms of the boom in the fully collapsed condition thereof, this section being taken generally on line 8-8, FIG. 5.

FIG. 9 is a vertical transverse section taken generally on line 9-9, FIG. 8.

The boom forming the subject of the invention is shown as mounted on a fire truck 10 having a chassis 11 carried by front and rear wheels 12, 13 and having a front windshield 14 protecting the driver in a compartment at the front of the vehicle and this compartment being accessible through a side door 15. Immediately in rear of the drivers compartment is an upstanding rest 16 for the bottom arm of the boom, as hereinafter described, and which prevents the boom from coming in contact with the windshield 14 or interfering with the driver or his driving vision.

The boom embodying the present invention comprises a bottom arm 20 and a top arm 21 pivotally connected together at their ends, the bottom arm 20 having its opposite end pivotally mounted on a turntable indicated generally at 22, and the top arm 21 carrying a platform 23 which carries one or more of the firemen as well as one or more large water nozzles 24 and which platform is maintained in a level position in all positions of the arms 20, 21.

The turntable 22 can be of any suitable construction and is shown as mounted on the horizontal top plate 25 of a container 26 for extensible, outrigger, ground-engaging stiff arms indicated generally at 27, these outrigger arms forming no part of the present invention and hence not being illustrated in detail. The container 26 forms part of the rear end of the body of the fire truck 10 having a bottom plate 28 mounted on a pair of the main longitudinal beams of the chassis 11 as best shown in FIG. 2. The drive for the turntable 22 comprises a horizontal stationary ring gear 29 secured, as by screws 30, to the top plate 25 and having radially inwardly projecting gear teeth 31. The ring gear 29 has its top face formed to provide a large concentric race for an annular series of ball bearings 32, these ball bearings being also contained in a race in the bottom of a turntable plate 33. To prevent displacement of this plate it preferably has a ring 34 secured, as by screws 35, to the underside of its rim, the inner. circular face of this ring being in close proximity to the periphery of the ring gear 29. The turntable plate 33 is shown as turned by means of a pinion 36 fast to a vertical shaft 38 suitably journalled on the turntable plate 33 and engaging the teeth 31 of the stationary ring gear 29. This pinion can be driven in either direction in any suitable manner as by a motor (not shown) under control of the firemen on the platform 23 by means of a control mechanism (also not shown).

Both the stationary top plate 25 and the bottom plate 28 of the container 26 for the outrigger stiff arms 27 are provided with vertically aligning holes concentric with the ring gear 29 and through which a large Vertical water pipe 41 extends through which water for fire fighting purposes is supplied to the nozzle or nozzles 24 carried by the platform 23. This vertical water pipe 41 swings with the turntable plate 33 and for this purpose is connected by a water-pipe swivel joint 42 with a stationary horizontal water supply pipe 43 secured to the chassis 11. A water pipe T 44 is secured, as by a coupling 45, to the upper end of the vertical pipe 41 and to each of its horizontally extending branches is secured, as by a coupling 46, horizontally aligning, cylindrical tubular trunnions 48. Water is supplied from the T 44 through each of these trunnions 48 throughswivel joints 49 to a pair of water pipes 50 secured to the exterior of and extending along opposite sides of the bottom arm 20 of the boom to the outboard end thereof.

Each of the two trunnions 48 is carried by a pair of axially spaced rings 53, each of these rings being mounted at the apex of an upstanding vertical plate 54 which is triangular in elevation as shown in FIG. 1. These plates are arranged in parallel relation to each other and have their bases secured, as by welding, to the turntable plate 33 so as to swing therewith, along with the trunnions 48, T 44 and vertical water pipe 41.

The bottom arm 20 of the boom is preferably constructed and journalled on the pair of trunnions 48 as follows:

The bottom arm 20 of the boom is preferably generally of uniform cross sectional size and form throughout its length with the exception of its opposite jou-rnalled extremities and to this end comprises an outer sheet metal shell 55 which is generally of U-shaped form in cross section to provide an upwardly opening channel 56 extending the full length thereof and as best shown in FIGS. 7, 8 and 9 having a bottom wall 60, vertical side walls 61 forming upward integral continuations of the outer longitudinal edges of the bottom wall 60 and top flanges 62 forming lateral integral continuations of the upper edges of the side walls 61 and being in opposed relation to each other. A heavy internal reinforcing bottom plate 63 is preferably secured to the upper face of the bottom wall 60 of the shell 55, and vertical reinforcing side plates 64 have their upper longitudinal edges secured to the inner extremities of the flanges 62 and have their lower edges welded to the reinforcing bottom plate 63. Transverse gussets 65 can be provided at intervals across the space between the side walls 61 and vertical reinforcing walls 64 and suitably welded in place to reinforce the bottom arm 20 of the boom.

As best shown in FIG. 3 the inboard end of the bottom arm 20 of the boom is closed by a cross plate 66 which can be welded in place and the side walls 61 of the arm embrace and are welded to a bearing 68, each embracing the corresponding trunnion 48, as best shown in FIGS. 2 and 3. Spacer rings 69 are preferably provided between each bearing 68 and the pair of rings 53 supporting each trunnion 48 and suitable stops 70 are preferably provided to keep the trunnions 48 axially positioned with reference to their supporting rings 53.

The bottom arm 20 of the boom is raised and lowered to any desired elevation by a telescopic hydraulic lift or ack indicated generally at 72. This hydraulic lift comprises a cylinder 73 containing a piston at the end of a piston rod 74, the outboard end of the latter being pivotally connected, .as indicated at 75, to a bracket 76 fixed to the underside of the bottom boom .arm 20. Theclosed end 78 of the cylinder 73 is pivotally connected, as indicated at 79, FIG. 3, to an ear 80 projecting upwardly and rearwardly from a cross plate 81 secured at its opposite ends along the inclined rear edges of the four triangular vertical plates 54 which pivotally support the bottom arm 20 of the boom, as previously described. When this bottom arm is in its lower most position and supported on the rest 16, FIG. 1, the telescopic hydraulic lift or jack 72 is angularly disposed with reference to the bottomboom arm so that when fluid is introduced into the closed end 78 of the cylinder 73, by controls (not shown) at the platform 23, the projection of the piston rod 74 will raise the bottom boom arm 20, as illustrated by the dot-dash showing in FIG. 1.

At the outboard end of the bottom arm 20 of the boom, the side walls 61 of the shell 55 of this arm are extended longitudinally and carry a pair of horizontally axially alining bearing sleeves 83 welded therein as best shown in FIG. 5. Each of these bearing sleeves 83 is preferably additionally supported by a vertical plate 84 welded to the bottom boom arm 20 to project from the endmost gusset 65, and an end plate 85 joins the outboard end of each of these vertical plates 84 with the side wall 61 of the bottom boom arm shell 55.

A horizontal shaft 86 is journalled in bearing bushings 88 in these axially alining bearing sleeves 83 at the outboard end of the bottom arm 20 of the boom, and between these two beariug sleeves 83 a second pair of hearing sleeves 89 are journalled on this shaft 81 by means of bearing bushings 90. These bearing sleeves 89 are welded to the inboard end of the top arm 21 of the boom which is preferably constructed as follows: 7

The top arm 21 of the boom is of tapering form in a vertical direction only, diminishing in vertical cross sectional size from its inboard to its outboard end and comprises a sheet metal shell 91 which at its inboard end is generally of inverted U-shaped form in cross section to provide at its inboard end a downwardly opening channel 92 and as best shown in FIGS. 2, 7, 8 and 9 having a top Wall 93, vertical side walls 94 forming downward integral continuations of the outer longitudinal edges of the top Wall 93, and bottom flanges 95 forming lateral integral continuations of the lower edges of the side walls 94 and being in opposed relation to each other. Along the inboard end of the top boom arm 21 a heavy reinforcing top plate 96 is preferably secured to the inner face of the top wall 93-01. the shell 92 and along the outboard end of the top boom arm a bottom plate 97 is welded and bridges the space between the flanges 95 to provide a box cross section. Transverse gussets 98 and 98' can be provided at intervals across the interior of the shell 91. The bearing sleeves 90 are welded in the side walls 94 of the top arm 21, these side walls being preferably internally reinforced at these bearing sleeves by face plates 99 as shown in FIG. 5.

Itwill particularly be noted that the axis of the horizontal shaft 86 is close to the bottoms of both boom arms 20 and 21 and, as best shown in FIGS. 1 and 8, this location of this axis insuring the nesting of the inboard end of the top boom arm 21 in the outboard end of the bottom boom arm 20 to reduce the overall height of the boom in its fully lowered position to permit the vehicle to be moved into and out of garage doorways of normal height for fire equipment. To this end also the inboard end to the top boom arm 21 is arranged wholly within the channel of the bottom boom arm 20 in the fully lowered condition of the boom.

The outboard extremity of the top arm 21 is shown as being in the form of a transverse end plate 100, FIG. 6, welded to the end edges of the shell 91 and having integral side continuations forming horizontally alining side ears 101 carrying horizontally axially alining bearing sleeves 102. Preferably these ears are reinforced by external gussets 103 extending longitudinally and welded to the exterior of the side Walls 94 of the shell 91 of the top arm 21, and each bearing sleeve 102 carries a bearing bushing 104 in which a cross shaft 105 is journalled. Split rings 106 or equivalent stops prevent axial displacement of the shaft 105 from the bearing sleeves 102.

The platform 23 is fixed to this cross shaft 105 and for this purpose the vertical rear wall 107 is provided with a pair of horizontally alined, transversely spaced ears 108 and 109 projecting horizontally rearwardly therefrom. The car 108 embraces and is Welded to a sleeve 110 secured by a key 111 to the shaft 105. The car 109 embraces and is welded to the hub of a bevel gear 112 the rim of this gear being flattened at one side, as indicated at 113 and welded to the rear wall 107 of the platform. Washers 114 are interposed between the bearing bushings 104 and the sleeve 110 and hub of the bevel gear 112.

This bevel gear forms part of a novel mechanism maintaining the platform 23 level in all positions of the boom arms 20, 21 with reference to each other and to the turntable 22. To this end a bevel pinion 115, FIG. 6, meshes with this bevel gear 112 and is journalled in a bearing bushing 116 within a bearing block 117 welded in the cross plate 100 at the outboard end of the top arm 21 of the boom. The axis of this hearing bushing 116 extends lengthwise of the top arm 21 of the boom and its hub is welded to the end of a tubular shaft 118 housed within keyed, as indicated at 123, FIG. 5, to the shaft 88. The

opposite ends of this shaft 88 project outwardly from the side walls 61 of the bottom boom arm 20 and have keyed thereto, as indicated at 124, lever arms which proje'ct downwardly in the lowered position of the bottom boom arm 20. A spacing washer 126 is interposed between the hub of each of these lever arms 125 and hearing sleeve 83 and split rings 128 or equivalent stops prevent axial displacement of the shaft88 from the bearing sleeves 83. A parallelogram rod 129 connects the outer end of each lever arm 125 with a pin 130 projecting, as best shown in FIGS. 3 and 4, horizontally outwardly from each outermost vertical plate 54 of the turntable 22 on which its bottom arm 20 of the boom is journalled.

These coaxial pins 130 are arranged so that the rod 129 is parallel with the boom and the connection between each pin 130 and its rod 129 is through an adjustable bearing 131 as shown in FIG. 4. The parallelogram rod 129 can be supported intermediate its ends by one or more links 132.

The top boom arm 21 is raised and lowered relative to the bottom boom arm 20 by a telescopic hydraulic lift indicated generally at 135. It is a feature of the inven tion that this hydraulic lift nests within the channels 56 and 92 of these boom arms in the collapsed position thereof as best illustrated in FIG. 8. I

To this end the hydraulic lift 135 is in the form of a cylinder 136 containing a piston actuating a piston 138 extensible from one end thereof through fluid pressure to the cylinder. The closed end 139 of the cylinder has an ear 140 projecting axially therefrom and connected by a pin 141 between the pair of ears 142 of a bracket 143 secured to the bottom plate 63 of the bottom arm 20 of the boom at a distance from the outboard end of the latter.

The free end of the piston rod 138 has ahead 144 connected by a pin 145 between a pair of ears 146 of bracket 148 secured to the top plate 96 of the top arm 21 of the boom close to the inboard end thereof.

The Water nozzles 24 are shown as supplied with water through water pipes 150 secured to the platform 23 and connected with the water pipes 50 alongside the bottom arm 20 of the boom in any conventional manner, this piping and the conventional water pipe swivel joints at the shaft 86 and pin 105 not being shown since they form no part of the present invention and would serve only to obscure pertinent structure.

In the operation of the apparatus forming the subject of the present invention it will be assumed that suitable control apparatus is present at the platform 23 for (1) controlling the rotation of the turntable 22 and stopping andholding it at any selected position, (2) raising and lowering the bottom arm 20 of the boom by applying pressurized fluid to the cylinder 73 of the hydraulic lift 72, (3) raising and lowering the top arm 21 relative to the lower arm 20 by introducing pressurized fluid into the cylinder 136 of the hydraulic lift 135, and (4) controlling the supply of water to the supply line 43, FIG. 2.

Upon reaching the fire, connections are first made for supplying water from a pumper to the supply line 43, and the fireman enters the platform 23 and elevates the lower arm 20 of the boom by so pressurizing its cylinder 73. The blind end of the cylinder is pivotally anchored on the turntable 22 (FIG. 3) and the extension of its piston rod 74 serves to lift this lower boom arm 20 from the rest 16 so that the fireman on the platform 23 is enabled to operate the turntable 22. At the same time the fireman on the platform 23 is raising the lower boom arm 20 he can also be pressurizing the closed end 139 of the cylinder 136. Since this closed end is pivotally anchored on the bottom boom arm 20 as shown in FIG. 8 the extension of its piston rod 138 serves to push the top boom arm 21 out of nested relation with the bottom boom'arm 2t) and to lift this top boom arm.

Accordingly, the operator on the platform 23 is now being lifted by the assumed rising movement of the two arms 20 and 21 of the boom and at any time he can also operate a control (not shown) on the platform 23 to turn the pinion 36, FIG. 3, in either direction. This pinion is journalled on the underside of the turntable plate 33 and since it engages the teeth 31 of the stationary ring gear 39 this rotation of the pinion 36 serves to rotate the turntable plate 33 in a corresponding direction. This rotates the standards or triangular plates 54 supporting the rings 53 carrying the tubular trunnions 48 and hence rotates these trunnions. Since the bearings 68 at the inboard end of the bottom arm 20 of the boom are journalled on these trunnions 48, this also swings this lower boom arm 20 in a cor-responding direction. Since the bearing sleeves 89 of the upper boom arm 21 are journalled on the shaft 86 which is also journalled in the bearing sleeves 83 at the outboard end of the lower boom arm 20, as illustrated in FIG. 5, this rotation of the plate 33 of the turntable 22 also rotates this upper boom arm 21 in a corresponding direction.

Accordingly, by suitable manipulation of the controls (not shown) on the platform 23, the fireman on this platform can swing the two arm boom about the axis of the turntable 22 supporting the boom so as to project this two arm boom in any direction and he can also raise or lower the lower boom arm 20 relative to its turntable 22 or raise or lower the top boom arm 21 relative to this bottom boom arm. It will be seen that this provides a great degree of flexibility since it is possible to bring the boom arms 20, 21 to an almost vertical position and hence raise the platform 23 to a great height and it is also possible to rotate the turntable to bring the lower boom arm 20 to a position where it is directed away from a high obstruction, such as a wall, raise or lower boom arm 20 to an eleva tion above the obstruction, and then to lower the top boom arm 21 so as to lower the platform 23 to a position below and on the opposite side of the top of the assumed obstruction,

While the fireman on the platform 23 is so rotating the turntable 22 he is also rotating the water pipe T 44 connected with the inboard ends of the tubular journals 48 as well as the vertical pipe 41. Since this vertical pipe 41 is connected to the water supply pipe 43 by the water pipe swivel 42 shown in FIG. 2, this rotation of the tumtable 22 and the boom supported thereon is permitted without interfering with the supply of water to the platform. Similarly, the raising and lowering of the lower boom arm 20 raises and lowers the water supply pipes 50 secured to its opposite sides, this being permitted by the water pipe swivel 49 arranged coaxially with its pivot axis as best shown in FIG. 2.

Water from these pipes 50 is supplied to the pipes 150 on the platform 23, by conventional piping and swivels which, for clarity of illustrationof the features of the present invention, are not shown. Accordingly when the operator on the platform 23 turns on the water supply to the supply pipe 43, FIG. 2, water is supplied to the nozzles 24.

A feature of the invention is that during this manipulation of the turntable 22 and arms 20, 21 of the boom, the platform 23 is maintained level. Thus, on raising the bottom boom arm 20, the parallelogram rods 129, which are maintained parallel with this bottom boom arm 20 by virtue of their connection to the pins 130* on the turntable 22, FIG. 4, and the effective length and position of the lever arms 125, swings these lever arms 125 counterclockwise as viewed in FIG. 1 thereby to rotate the shaft 86,

FIG. 5 in a corresponding direction. This rotates the bevel gear 122, pinion 119 and longitudinal shaft 118 and also, FIG. 6, bevel pinion and gear 112 in a direction to maintain the platform 23 level during this raising of the lower boom arm 20 this being occasioned by the bevel pinion 112 being welded to the rear wall 107 of this platform as best shown in FIG. 6.

When the fireman on the platform 23 raises the top arm 21 relative to the bottom arm 20 of the boom (assuming the latter to be stationary for simplicity of explanation) the bevel pinion 119, FIG. 5, is caused to walk along the teeth of the assumed to be stationary gear 122 thereby to rotate this pinion 119, its shaft 118 as well as, FIG. 6, the bevel pinion 115 and gear 112 fixed to the rear wall 107 of the platform 23, again to maintain the platform 23 level.

After the firefighting service is finished, the fireman on the platform 23 actuates the pinion 36, FIG. 3, on the plate 33 of the turntable 22 to move this turntable plate 33 about the stationary ring gear 29 and bring the arms 20,, 21 of the boom ,in line with the rest 16. The operator then relieves pressure from the blind or closed ends 78 and 139 of the cylinders 73 and 136 of the high lifts 72 and for the boom arms 20 and 21, respectively. This causes both arms 20 and 21 of the boom to descend and an important feature of the invention is that in doing so the inboard end of the top arm 21 of the boom nests within the channel 56 at the outboard end of the bottom arm 20 of the boom, the latter being of upwardly opening U-shaped form in cross section for this purpose. By virtue of such nesting, when both boom arms 20, 21 reach their lowermost position with the outboard end of the lower boom arm 20 supported on the rest 16 the high point of the boom at the front end of the vehicle is no greater than the high point of the lower boom arm alone.. Accordingly the rest 16 can be made high enough so that the lower boom arm 20 in its depressed position is above the windshield 14 as well as above the driver and occupants of the drivers compartment behind the doors 15, the driver having full visibility forwardly and also to opposite sides of the roadway. The driver can therefore drive the apparatus to the firehouse and when he reaches the firehouse, the nested condition of the boom arms 20, 21 with reference to each other again becomes important. Thus, since the high point of the nested boom structure, as illustrated by full lines in FIG. 1, is the same as the high point of the bottom arm 20 of the boom alone, the apparatus can be driven through a firehouse garage door of normal height without further change in the apparatus.

Conversely, on the next fire alarm requiring the apparatus, the driver can move the vehicle out of the garage door of the firehouse and proceed directly down the road without requiring the boom to be first elevated a slight degree and a folding windshield to be swung into operative position.

It will also be noted from FIG. 8 that the high lift 135 for the top boom arm 21 does not interfere with the nesting of this top boom arm in the channel 56 of the bottom boom arm 20 but in fact itself nests within the channels 56 and 92 of these boom arms.

From the foregoing it will be seen that the present invention accomplishes, in a very simple, sturdy and positively acting structure the principal objects of the invention, namely minimizing maximum height of the boom to enter the garage doorways of firehouses without difiiculty, this being efiected by nesting the pivotally connected ends of the boom arms 20, 21, one within the other, supplying water to the boom arms from a supply line contained wholly within the turntable 22, this being accomplished by the tubular trunnions 48 and the water pipe T 44 supplying water through these Ts to the water pipe swivels 49 and water pipes 50 alongside the bottom arm 20 of the boom; and maintaining the platform 23 level through a simple structure contained within the top arm 21 of the boom, this being accomplished by the rotating shaft 119 and bevel gears 112, 115, 119 and 122 connected therewith.

We claim:

1. In a vehicle having a wheel supported chassis, a turntable supported on said chassis, horizontal axis hearing means mounted on said turntable, and means adapted to rotate said turntable; the combination therewith of a double boom, comprising a bottom arm journalled on said bearing means, said bottom arm being channelshaped in cross section with its channel opening upwardly and having a sheet metal bottom wall, side walls forming integral upward continuations of the side edges of said bottom wall, a flange forming an integral inward continuation of the upper edge of each of said side walls, a vertical plate joined at its upper edge to each of said flanges and means operatively connecting the lower edge of each of said vertical plates to said bottom wall, means adapted to raise and lower said bottom arm about said horizontal axis bearing means with reference to said turntable, a top arm journalled on the outboard end of said bottom arm for rotation about a second axis generally parallel with said first mentioned axis, means adapted to raise and lower said top arm about said second axis with reference to said bottom arm, said top arm "moving into and out of the channel of said bottom arm as said arms move to and from their fully retracted position, with the inboard end of said top arm arranged substantially fully within the channel of the bottom arm in the fully lowered condition of the boom, thereby to reduce the elevation from the ground of the high point of said arms at the outboard end of said bottom arm to facilitate movement of the vehicle through garage doors and the like.

2. The combination set forth in claim 1 wherein said connecting means comprising a bottom plate is secured to the top of said bottom wall and to the lower edges of said vertical plates.

3. In a vehicle having a wheel supported chassis, a turntable supported on said chassis, means adapted to rotate said turntable, a boom arm, means operatively connecting the inboard end of said boom arm with said turntable to swing about a horizontal axis, means for raising and lowering said boom arm about said axis and a platform pivoted on the outboard end of said boom arm to swing about a second axis parallel with said first mentioned axis; the combination therewith of means maintaining said basket level in all positions of said boom arm, comprising'a shaft jou-rnalled on said boom arm and extending longitudinally substantially the full length thereof, gear and pinion means connecting said platform with the adjacent end of said shaft to swing said platform about its axis in response to rotary movement of said shaft, and means operatively connected with the opposite end of said shaft and turning the same in response to movement of said boom arm about said first mentioned axis to maintain said platform in a level position.

4. In a vehicle having a wheelsupported chassis, a turntable supported on said chassis, means adapted to rotate said turntable, a bottom boom arm, means journalling the inboard end of said bottom boom arm on said turntable to swing about a horizontal axis, means for raising and lowering said bottom boom arm about said journalling means, a top boom arm means journalling the inboard end of said top boom arm on :the outboard end of said bottom boom arm to swing about an axis parallel with said first mentioned axis, means for raising and lowering said top boom arm relative to said bottom boom arm, and a platform pivoted on the outboard end of said top boom arm to swing about an axis parallel with said axes; the combination therewith of means maintaining said platform level in all positions of said top and bottom boom arms, comprising a shaft journalled on said top boom arm and extending longitudinally substantially the full length thereof, gear and pinion means connecting said platform with the adjacent end of said shaft to swing said platform about its axis in response to rotary movement of its shaft, and means operatively connected with the opposite end ofsaid shaft and turning the same in response to relative movement between said top boom arm and said bottom boom arm and turntable to maintain said platform in alevel position.

5. In a vehicle having a wheel supported chassis, a turntable supported on said chassis, means adapted to rotate said turntable, a bottom boom arm, means journalling the inboard end of said bottom boom arm on said turntable to swing about a horizontal axis, means for raising and lowering said bottom boom arm about said journalling means, a first shaft journalled at the outboard end of said bottom boom arm and arranged parallel with said axis, a top boom arm having its inboard end journalled on said first shaft, means for raising and lowering said top boom arm relative to said bottom boom arm, and a platform pivoted on the outboard end of said top boom arm to swing about an axis parallel with said first mentioned axis; the combination therewith of means maintaining said platform level in all positions of said top and bottom boom arms, comprising a second shaft journalled on said top boom arm and extending longitudinally substantially the full length thereof, gear and pinion means connecting said platform with the adjacent end of said second shaft to swing said platform about its axis in response to the rotary movement of said second shaft, gear and pinion means connecting the opposite end of said second shaft with said first shaft and turning said second shaft in response to turning movement of said first shaft, and means turning said first shaft in response to relative movement between said bottom boom arm and turntable to maintain said platform in a level position.

6. The combination set forth in claim 5 wherein last named means comprises a control arm fixed to said first shaft and projecting laterally with reference to said bottom boom arm, a rod pivotally connected to the outer end of said control arm and extending along said bottom boom arm to the inboard end thereof, and means pivotally connecting the end of said rod opposite said control arm to said turntable at a point where said rod is maintained parallel with said bottom boom arm in all positions of elevation of the latter.

7. The combination set forth in claim 5 wherein each of said gear and pinion means is in the form of an. intermeshing bevel gear and pinion.

8. In a vehicle having a wheel supported chassis, a turntable supported on said chassis, a first horizontal axis bearing means mounted on said turntable, and means adapted to rotate said turntable; the combination therewith of a double boom arm, comprising a bottom arm having its inboard end journalled on said first bearing means, said bot-tom arm being channel-shaped in cross section with its channel opening upwardly and having a sheet metal bottom wall extending substantially the full lengththereof and side walls extending substantially the fully length of said'bottom wall and each joined along its lower edge to the corresponding longitudinal side edge of said bottom wall, a second horizontal bearing means at the outboard end of said bottom arm with its axis arranged parallel with said first axis and close to the outer extremity of said bottom wall and remote from the top edges of said side walls, means adapted to raise and lowersaid bottom arm about said first horizontal axis bearing means with reference to said turntable, a top arm having its inboard end arranged between said 7 side walls of said bottom arm and journalled at its inboard end on said second horizontal bearing means close to the bottom longitudinal side and remote from the top longitudinal side of said top arm, means nesting in the channel of said bottom arm adapted to raise and lower 11 12 said top arm about said second horizontal axis with ref- References Cited by the Examiner erence to said bottom arm, said top arm moving into UNITED STATES PATENTS and out of the channel of said bottom arm as said arms move to and from their fully retracted position, with said 3871887 8/1888 Kahnskl 182' 52 inboard end of said top arm arranged substantially fully 5 29693349 1/1961 Grant 182-3 Within the channel of the bottom arm in the fully low- 31064754 11/1962 Broderson 182 2 'ered condition of the boom, thereby to reduce the ele- 35072215 1/1963 Rflsh 182-2 vation from the ground of the high point of said arms 31103257 9/1963 Rlchards 182 2 at the outboard end of said bottom arm to facilitate HARRISON RMOSELEY, Primary Examiner movement of the vehicle through garage doors and the 10 1i REINALDO P. MACHADO, Examiner. 

3. IN A VEHICLE HAVING A WHEEL SUPPORTED CHASSIS, A TURNABLE SUPPORTED ON SAID CHASSIS, MEANS ADAPTED TO ROTATE SAID TURNTABLE, A BOOM ARM, MEANS OPERATIVELY CONNECTING THE INBOARD END OF SAID BOOM ARM WITH SAID TURNTABLE TO SWING ABOUT A HORIZONTAL AXIS, MEANS FOR RAISING AND LOWERING SAID BOOM ARM ABOUT SAID AXIS AND A PLATFORM PIVOTED ON THE OUTBOARD END OF SAID BOOM ARM TO SWING ABOUT A SECOND AXIS PARALLEL WITH SAID FIRST MENTIONED AXIS; THE COMBINATION THEREWITH OF MEANS MAINTAINING SAID BASKET LEVEL IN ALL POSITIONS OF SAID BOOM ARM, COMPRISING A SHAFT JOURNALLED ON SAID BOOM ARM AND EXTENDING LONGITUDINALLY SUBSTANTIALLY THE FULL LENGTH THEREOF, GEAR AND PINION MEANS CONNECTING SAID PLATFORM WITH THE ADJACENT END OF SAID SHAFT TO SWING SAID PLAT- 